Copolyetherimide esters and copolyether esters are well known in art and have been referred to as elastomers. However, in certain applications, it is necessary that such esters be rendered flame retardant where fire can result from the burning of the thermoplastic resin and which can then further contribute to the burning of other combustibles in the immediate area. While halogens, particularly bromine containing compounds, have found usefulness in thermoplastic resins as flame retardant additives, there is, however, the need to move away from such halogen compounds and into non-halogen flame retardants because of the impact halogens have on the environment. However, obtaining successful non-halogen flame retardants with copolyetherimide esters or copolyether esters is not obvious because of the complex nature of the thermoplastic resins of this invention.
Japanese patent publication JP62161850 discloses a vinyl chloride graft polymer such as ethylene vinyl acetate flame retarded with calcium carbonate and magnesium hydroxide with clay and silica.
European patent disclosure EP230564 discloses a flame retarded rubber flooring composition, containing in combination aluminum hydroxide and either calcium carbonate, magnesium hydroxide or magnesium oxide in combination with zinc borate, antimony trioxide or antimony pentoxide.
It has now been discovered that flame retarded polymers of the type disclosed above, namely copolyetherimide esters and copolyether esters, can be obtained employing a particular non-halogen flame retardant. It is surprising that certain hydrated minerals provide a flame retardant composition of this invention that can be molded into a finished article. Other mineral flame retardants have been tried but the resulting composition cannot be injection molded. The mineral flame retardants of this invention have a higher decomposition temperature than other non-mineral flame retardants. However, it has been surprisingly discovered that only certain hydrated minerals are capable of producing the flame retarded moldable thermoplastic compositions of this invention.